In underground mining, the shearer loaders normally used for extracting coal are moved along a conveyor which can be advanced in the direction of working and which is overlapped by the machine body of said shearer loaders and which, in addition to guide rails for the shearer loader, also comprises a rack arrangement which is usually formed by rack bars or a chain and in which the drive sprocket of a drive subassembly of the shearer loader engages from above with its teeth. The shearer loader can then be moved along the rack arrangement by motor-operated drive of the drive sprocket. In addition, in order to ensure the reliable engagement of the tooth system of the drive sprocket in the chain or rack bar of the rack arrangement, the drive subassembly is guided on the rack arrangement by means of at least one guide element or guide shoe. On account of the high reaction forces during coal mining, on account of the high weight of the shearer loader and on account of rock fragments or the like which can possibly fall into the rack, in particular the wear of the drive sprocket of the shearer-loader drive subassembly and the wear of the guide elements is relatively high. There is therefore a fundamental need to be able to exchange the guide elements, such as the guide shoe for example, and the drive sprocket as quickly and as simply as possible if wear occurs.
In the shearer-loader drive subassembly known from DE 37 18 442 C1, the drive sprocket sits on a drive shaft which is rotatably supported with its one end in the housing base plate by means of fluid mounting. The drive shaft is supported by means of further housing plates, which for this purpose are arranged at a distance from the housing base plate. In order to ensure the sliding mounting of the drive shaft in the housing base plate, the bearing space for the intermediate gear and a gear meshing with the latter and sitting on the output shaft of the drive motor is designed to be fluid-tight.
In the shearer-loader drive subassembly of the generic type known from DE 197 12 774 A1, the drive sprocket is screwed to the transmission gear and, after removal of a cap opposite the housing base plate, can be removed together with the bearing tube and the bearings. The guide shoe comprises a specially designed hook which engages both underneath and behind a bottom guide strip on a rack bar or the like. The assembly cost and changeover cost is relatively high, since in the event of a repair a construction unit consisting of drive sprocket, transmission gear, bearings and bearing shaft has to be dismantled. The dismantling therefore cannot be carried out without lifting gear.
The object of the invention is to provide a shearer-loader drive subassembly and a guide shoe for it which permit simple fitting or removal, which can be carried out quickly, of the wearing parts such as, in particular, drive sprocket and guide shoe.
This object is achieved according to the invention in the case of the shearer-loader drive subassembly in that the guide shoe is fastened to the base plate by means of a releasable pin which passes through the inner bore of the bearing tube and forms the pivot bearing for the guide shoe, and/or in that a bearing sleeve rotatably supported on the bearing tube by means of at least one bearing is arranged between the drive sprocket and the bearing tube, onto which bearing sleeve the drive sprocket is pushed or can be pushed in a releasable manner from the bearing tube end remote from the housing base plate. In the solution according to the invention with regard to the guide shoe, it is only necessary for a pin serving at the same time as a pivot bearing for the guide shoe to be released and removed in order to then release the guide shoe preferably downward from the drive subassembly. In this case, this pin passes through the inner bore of the bearing tubes such that the pivot axis for the guide shoe coincides with the rotation axis of the drive sprocket. The removal of a pin enables the guide shoe to be removed extremely rapidly without other elements of the drive subassembly having to be released or removed for this purpose. The pivotable mounting of the guide shoe at the same time improves the guidance behavior of the drive subassembly on the rack arrangement and increases the service life of the guide shoe. A second solution concept according to the invention proposes, for the shearer-loader drive subassembly, a mounting of the drive sprocket in which only the drive sprocket, preferably after prior requisite removal of the guide shoe, is removed, whereas all the subassembly elements serving for mounting the drive sprocket and the bearings remain in the fitted state in the drive subassembly. By means of this measure, which is achieved by virtue of the fact that the drive sprocket is fastened only indirectly in the drive subassembly, with a bearing sleeve in between which is rotatably supported on the bearing tube, the fitting or removal of the drive sprocket is considerably simplified. For the fitting or removal of the drive sprocket, it is no longer necessary to fit or remove the bearing tube together with associated mounting, since the bearing tube remains fastened to the housing base plate.
In a preferred configuration of a shearer-loader drive subassembly, the bearing sleeve is rotatably supported on the bearing tube by means of a single bearing arranged in a bearing section of the bearing sleeve and has a sleeve section which extends up to a second bearing, onto which the hub of the transmission gear is pushed, preferably directly. The sleeve section of the bearing sleeve therefore at the same time provides for the requisite distance of the bearing or bearing section of the bearing sleeve from the second bearing. This distance is required in order to be able to fit the drive sprocket and arrange it next to the transmission gear. It is especially advantageous if the bearing tube and the bearing sleeve each comprise a shoulder for arranging the first bearing, which shoulders firstly restrict or minimize the axial play of bearing and bearing sleeve and secondly ensure that the respective tube thicknesses of the bearing tube and the bearing sleeve do not become excessively large. The first and/or the second bearing can preferably consist of twin-row antifriction bearings.
In the especially preferred configuration, the drive sprocket is releasably screwed to the transmission gear by means of axial screws. The rotationally locked connection between drive sprocket and transmission gear is expediently assisted by means of feather keys and/or a splined shaft connection between the two gears in order to protect the axial screws from shearing loads. According to an advantageous configuration, the drive sprocket, on a side wall, comprises a collar which engages in a rotationally locked manner in a recess in the side flank of the transmission gear. In an especially advantageous configuration, the drive sprocket, on the opposite side wall, may then have an annular collar which extends beyond the first bearing up to the free sleeve end, remote from the housing base plate, of the bearing sleeve and which is preferably provided with a circumferential groove for the engagement of a pull-off tool or the like for the drive sprocket. In this configuration, provision may be made at the same time for the annular collar to be provided with a spherical surface. During operational use, the drive sprocket can then at the same time roll on the top side of the rack arrangement by means of the spherical surface of the annular collar.
According to an especially advantageous configuration of the shearer-loader drive subassembly according to the invention, the guide shoe is of one-piece design and has a base wall having a guide extension for engaging underneath the rack arrangement and, opposite the base wall, an opposing wall having a guide extension for engaging behind the rack arrangement. A one-piece guide shoe which not only engages underneath the rack arrangement but at the same time also engages behind it ensures that the drive subassembly of the shearer loader is reliably guided on the rack arrangement both vertically and transversely to the direction of movement of the shearer loader and disengagement of the drive sprocket from the rack bar or chain of the rack arrangement is effectively prevented. The guide shoe can be fitted or removed in an especially simple manner if the pin projects on both sides from the bearing tube and, for the pivotable mounting of the guide shoe, engages in through-openings in the base wall and the opposing wall of the guide shoe. The pin may consist in particular of a one-piece push-in pin which is secured against release in its fitted position by suitable pin retention means.
The above object is preferably achieved in the case of a guide shoe according to the invention in that a first through-opening formed in the base wall is provided in alignment with a second through-opening formed in an opposing wall opposite said base wall, the two through-openings serving for the engagement and passage of a pin, which can be inserted into a subassembly-side bearing tube, for the pivotable mounting and support of the guide shoe. The guide shoe pivotably mounted on two opposite walls can not only be completely removed by simple removal of the pin, but is at the same time advantageously supported over its entire width for pivoting. It is also especially advantageous in the case of the guide shoe if it is of one-piece design and has a base wall having a guide extension for engaging underneath the rack arrangement and an opposing wall having a guide extension for engaging behind the rack arrangement. A space open at the top and bottom is expediently formed between the base wall and the opposing wall, in which space, in the fitted state of the guide shoe on the drive subassembly, the drive sprocket is arranged in a plunging manner in such a way that its teeth can engage in the rack arrangement.